Ubuntu-Grub Madness ! Arrrgh !

killpotts · 03-10-2009, 02:24 PM

Hello all.

I've been trying to install to an external Hard drive for quite some time, and I finally had some success in that all the files for boot have made it to the external device. Unfortunatly, despite that fact that I went into advanced and made sure GRUB was to be installed on the external, it still failed anywayy and I get a Grub error 21 when I attempt to boot from USB ( go figure. )

So now I am back in the live CD trying to figure out how to fix grub.

This is what I tried:

Code:

ubuntu@ubuntu:~$ sudo -s
root@ubuntu:~# fdisk -l

Disk /dev/sda: 80.0 GB, 80026361856 bytes
255 heads, 63 sectors/track, 9729 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x3c9e3c9d

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *         767        9729    71995297+   7  HPFS/NTFS
/dev/sda2               1         766     6152863+   b  W95 FAT32

Partition table entries are not in disk order

Disk /dev/sdb: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x000065c7

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *           1         305     2449881   83  Linux
/dev/sdb2             306       19457   153838440    5  Extended
/dev/sdb5           17901       19457    12506571   82  Linux swap / Solaris
/dev/sdb6             306       17180   135548374+  83  Linux
/dev/sdb7           17181       17900     5783368+  82  Linux swap / Solaris

Partition table entries are not in disk order
root@ubuntu:~# grub-install /dev/sdb1
Probing devices to guess BIOS drives. This may take a long time.
Could not find device for /boot: Not found or not a block device.

*Sdb is my external device that I tried to install linux to.

So basically I can't install Grub to the Boot partition because it "can't find device for /boot:" ? So it recognizes that its a boot sector but at the same time thinks it is not ?

I'm stumped

Is there anything I can do to fix Grub that can be done from the Live CD ?

yancek · 03-10-2009, 04:46 PM

Do you get this error with your external USB set to first boot priority in the BIOS? What does your menu.lst file look like? Can you post it?

Drakeo · 03-10-2009, 07:10 PM

Here is the problem if your booting from a usb drive your machine must have that ability to boot directly from bios to that drive. b error 21

Quote:

21 : "Unknown boot failure"

This error is returned if the boot attempt did not succeed for reasons which are unknown.

grub looks for a folder /boot then creates a grub folder and places the system setup in there. as root type grubconfig now choose simple. and put it on /dev/sdb1 and the mbr of sdb1. the reason you are not getting it to go to the only reason I can think of it is not mounted mount /dev/sdb1 grubconfig /dev/sdb1 Place boot loader on MBR /dev/sdb make sure you can boot from an USB device.

killpotts · 03-12-2009, 03:13 AM

I managed to get it booting using ( Super Grub disk ). It works...problem Is grub is still somehow on the internal ( dying ) HD which just barely works. I got it working in a way that booting from main HD gets me through and good ( Grub pointing to external from the internal ) but I would really like it if there was some way so that I could boot from USB and have it work. Currently if I try to boot from USB in my bios, it gives me grub error 22.

I suspect that there simply MUST be a way, and my failure is largely due to the fact that I really didn't understand what I was doing while botting from the Super Grub Disk. If anyone has a beginner friendly guide on SGD that explains how to set this up ( or has done it themselves ), that would be great.

ronlau9 · 03-12-2009, 04:16 AM

To avoid problems if you're going to install on SDB and boot from SDB be sure that at the moment of install SDB is the first boot HD and install GRUB in MBR of SDB

Duck2006 · 03-12-2009, 07:14 AM

Can you post your menu.lst

Some info on grub.

http://users.bigpond.net.au/hermanzone/p15.htm